Combustion Performance of Liquid Biofuels in a Swirl-Stabilized Burner

Abstract

Fuels produced from renewable sources offer an economically viable pathway to curtail emissions of greenhouse gases. Two such liquid fuels in common usage are biodiesel and ethanol derived from soybean, corn, or other food crops. In recent years, significant effort has been devoted to identify alternate feedstock sources and conversion techniques to diversify the biofuels portfolio. In this study, we have measured emissions from flames of diesel, biodiesel, emulsified bio-oil, and diesel-biodiesel blends. Experiments are conducted in an atmospheric pressure burner with an air-atomized injector and swirling primary air around it to replicate typical features of a gas turbine combustor. Experiments were conducted for fixed air and fuel flow rates, while the airflow split between the injector and the coflow swirler was varied. Results show a significant reduction in emissions as the fraction of total air fed into the atomizer is increased. Blue flames, reminiscent of premixed combustion, and low emissions of nitric oxides and carbon monoxide were observed for all fuel blends. In general, the emissions from biofuel flames were comparable or lower than those from diesel flames.

Spray flame structure of rapeseed biodiesel and Jet-A1 fuel

“…Hashimoto et al [4] reported lower NO x emissions of palm methyl esters compared to diesel fuel in a swirling flame established from a pressure atomizer. Sequera et al [5] studied the rate of pollutant emission of biofuel flames using an airblast-injector type axial swirl combustor, in which the emissions of diesel, soy methyl ester, soy ethyl ester and bio-oil pyrolised from hardwood were compared. Lower emissions of NO x and CO were obtained for biodiesel-blended fuels when compared at the same fuel mass flow rate.…”

Performance Evaluation of Palm Oil-Based Biodiesel Combustion in an Oil Burner

“…Szybist et al [7] pointed out that compared to conventional diesel fuel (CDF) at high load, biodiesel blends generate 6%-9% higher NO x emissions. For gas turbine engines, Sequera et al [8] investigated the emissions of diesel and biodiesel using swirl burner gas turbine engines. Their results illustrated that biodiesel blended fuels emitted lower NO x and CO at constant fuel flow rates.…”

Spray Combustion Characteristics of Palm Biodiesel

“…Sequera et al [8] investigated the emissions of diesel, soy methyl ester, soy ethyl ester and bio-oil pyrolised from hardwood. Their results demonstrated that biodiesel blended fuels emitted lower NOx and CO at conditions where the fuel flow rates are kept constant.…”